lib/abstract_mapper/functions.rb in abstract_mapper-0.0.1 vs lib/abstract_mapper/functions.rb in abstract_mapper-0.0.2

@@ -8,12 +8,26 @@
   #
   module Functions
 
     extend Transproc::Registry
 
-    uses :map_array, from: Transproc::ArrayTransformations
+    import :map_array, from: Transproc::ArrayTransformations
 
+    # Returns the unchanged value whatever parameters are given
+    #
+    # @example
+    #   fn = Functions[:identity, :foo]
+    #   fn[1] # => 1
+    #
+    # @param [Object] value
+    #
+    # @return [Object]
+    #
+    def self.identity(value, *)
+      value
+    end
+
     # Applies the function to every element of array and removes empty values
     #
     # @example
     #   fn = Functions[:filter, -> v { v - 1 if v > 3 }]
     #   fn[[1, 4, 5, 3, 2, 5, 9]]
@@ -22,12 +36,12 @@
     # @param [Array] array
     # @param [Proc] fn
     #
     # @return [Array]
     #
-    def filter(array, fn)
-      map_array(array, fn).compact.flatten
+    def self.filter(array, fn)
+      t(:map_array, fn)[array].compact.flatten
     end
 
     # Applies the function to every consecutive pair of array elements,
     # and removes empty values
     #
@@ -42,11 +56,11 @@
     #   Anonymous function (proc, lambda), that takes two arguments
     #   and returns an array
     #
     # @return [Array]
     #
-    def compact(array, fn)
+    def self.compact(array, fn)
       array.each_with_object([]) do |i, a|
         if a.empty?
           a << i
         else
           a[-1] = fn.call(a.last, i)
@@ -65,11 +79,24 @@
     # @param [Module] subling
     # @param [Module] ancestor
     #
     # @return [Boolean]
     #
-    def subclass?(subling, ancestor)
+    def self.subclass?(subling, ancestor)
       subling.ancestors.include?(ancestor)
+    end
+
+    # Restricts the hash by keys and values of the default one
+    #
+    # @param [Hash] hash
+    # @param [Hash] default_hash
+    #
+    # @return [Hash] <description>
+    #
+    def self.restrict(hash, default_hash)
+      keys = default_hash.keys
+      values = default_hash.merge(hash).values
+      Hash[keys.zip(values)]
     end
 
   end # module Functions
 
 end # class AbstractMapper